With the File "/etc/cpanel_exim_system_filter" how do i make it so all error messages go to webmaster@example.com?

I originally had a script made in cpanel which says the following

if
error_message
then
save "/....../example.com/webmaster/" 660
endif

this correctly saved any error messages to the webmaster mailbox.

however it just moved the files there, so the original recipient did not receive an error message saying how,why and what time their email did not arrive at its destination.

so basically I need something which does the same thing, except it copies the file instead of moving it, with only the error message going to the webmaster mailbox, not the email sent which did not arrive.